Environmental and Experimental Biology (2021) 19: 7–10 Brief Communication http://doi.org/10.22364/eeb.19.02 Funnel trap as a method for capture migrating bats in Pape, Latvia
Oskars Keišs1*, Donats Spalis1, Gunārs Pētersons2 ISSN 2255-9582
1Laboratory of Ornithology, Institute of Biology, University of Latvia, Jelgavas 1, Rīga LV–1004, Latvia 2Faculty of Veterinary Medicine, Latvia University of Life Sciences and Technologies, Kristapa Helmaņa 8, Jelgava LV–3004, Latvia
*Corresponding author, E-mail: [email protected]
Abstract
We constructed a large funnel trap on the coast of the Baltic Sea on dunes of Pape village, Latvia. The trap has been used during the peak autumn migration of bats in Latvia in August and September. During the period of 2014 – 2020, about 40 thousand bats were captured in the trap, mostly Nathusius’ Pipistrelle Pipistrellus nathusii, about 35 thousand individuals. In migration hotspots of bats, this is suggested method of trapping since large number of bats might be trapped without entangling bats in mist-nets.
Key words: bat migration, funnel Heligoland trap, Pipistrellus nathusii.
Introduction bats could be observed and captured in great numbers in the trap (Celmiņš et al. 1986). Harp traps for bats (Tuttle Research on bird and bat migration usually includes also 1974; Masing 1989) were built inside the final tunnel of capture of animals. A problem with bird captures with the Rybatschi trap, but they were relatively ineffective in mist nets often arises when there are several hundred birds entangled in one mist-net and the capacity of ringers is limited. Bats during migration are usually scarce and there are too few captured due to lower concentrations of bats and higher migration altitude (mist nets are usually limited to 2 m above the ground). A funnel trap for bird research was first built on Heligoland Island, Germany in 1920 by Dr. Hugo Weigold (Weigold 1922; Weigold 1924; Weigold 1956; Woodford, Hussel 1961) and therefore later funnel traps for bird trapping have often been referred as “Heligoland traps”. However, funnel traps were constructed previously for trapping thrushes (Turdus spp.) for food (Gatke 1895). In 1957 in Rybatschi Ornithological station (former Vogelwarte Rossitten of Germany) on the Curonian Spit, a large Heligoland trap was designed and built by Jānis Jakšis and team of the station (Belopolskii 1961). This large Heligoland trap is also referred to as the “Rybatschi trap” (Payevsky 2000). Survey of the best place for establishing a bird observatory in Latvia for research of autumn migration of birds was done in autumn of 1958 (Mihelsons et al. 1960). The results of a month of observations between September 15 and October 15 indicated two locations with considerable bird concentrations: Salacgrīva and Pape (Fig. 1). The Bird Observatory at the Baltic Sea coast Fig. 1. Estimated numbers of migrating Passerine birds at coastal in Pape village was established in 1966 (Blūms et al. 1966; locations of Latvia, autumn 1958, when the choice to establish Baumanis 1995) and the first Rybatschi type trap was built Ornithological station in Pape was made (redrawn after Mihelsons in 1968. However, in 1985 it was noticed that also migrating et al. 1960).
7 O. Keišs. D. Spalis, G. Pētersons
Fig. 2. Scheme of the trap build in Pape in 2014 for bat trapping (drawing by Reinis Priedols). comparison to active trapping of bats flying in the tunnel removed in the middle of September. The trap can be lifted by butterfly net (Pētersons 2004). for catching, and lowered during storms, by six winches. Of the six poles with height 15 m, one broke in the 6th year of Construction of the funnel trap usage in 2019 (during a storm on September 10 when the trap was installed and lowered). This pole was replaced in An overall scheme of a Helgoland trap was published by 2020 before the beginning of the season. Woodford and Hussel (1961), but each Helgoland type and Rybatschy type trap varies depending on the local Scientific use of the trap relief and other characteristics of the surroundings and possibilities. The trap we designed and constructed in The trap has been very successful in capture of migrating 2014 in Pape, Latvia was aimed at bat capture during the bats. The total number of captured individuals of 15 bat autumn migration in August – September (before autumn species during the period 2014 – 2020 was 40 896 (Table storm season starts at the Baltic Sea). At the entrance it 1). The only Latvian bat species captured in Pape before was 15 m high and the end corridor was 2.0 m high; the this trap was build, in 1988 (Pētersons, Celmiņš 1989), width of the trap at the entrance was 35 m and 1.5 m at but not during the period of 2014 – 2020, was the greater the end corridor (Fig. 2). The mesh size was 18 × 18 mm at mouse-eared bat (Myotis myotis). The majority of the the beginning of the trap, 12 × 12 mm at the end corridor captured individuals (35 396) were Nathusius’ pipistrelles and 8 × 8 mm at the end box in order to prevent birds and (Pipistrellus nathusii), with maximum captures being 14 bats of smaller species to escape through the mesh at the 171 in 2018 (Table 1). On average during this period (2014 end of the trap. The trap was attached to six poles 15 m – 2020) there were more captures per year (5842) than ever high and two poles 3 m high (Fig. 3 and 4), produced in previously, up to 3975 in 1990 (Pētersons 2004), on average Latvia (“Jauda-Koks”, LV–5060 Suntaži) for electrical wires. 2546 per year (1988 – 1991). These data are given here only The poles are stationary in the field all year round, but the as an example, since explicit analyses of bat migration data trap is installed each year at the beginning of August and are given in specific articles (e.g., Petersons 2004; Lindecke
8 Funnel trap as a method for capture migrating bats
Fig. 3. Pape trap from above (photo by Jasja Dekker).
Fig. 4. Pape trap from Eastern (inland) side (photo by Gunārs Pētersons).
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Table 1. Number of bat species and individuals captured in the Pape trap in 2014 – 2020
Species / species group 2014 2015 2016 2017 2018 2019 2020 Total 2014 – 2020 Pipistrellus nathusii 1596 2172 4864 2038 14171 6583 3972 35396 Pipistrellus pipistrellus – – – 5 1 – – 6 P. pipistrellus / pygmaeus – – 1 – – – – 1 Pipistrellus pygmaeus 83 222 741 421 529 1171 595 3762 Nyctalus noctula 4 7 32 32 75 270 39 459 Nyctalus leisleri – 1 – – – 5 – 6 Vespertilio murinus 14 17 76 110 261 329 53 860 Eptesicus nilssonii 2 4 22 55 25 46 18 172 Eptesicus serotinus 2 1 1 3 8 7 2 24 Myotis dasycneme – 2 1 – – – – 3 Myotis daubentonii 2 2 7 9 7 10 12 49 Myotis brandtii 1 3 7 9 11 12 4 47 Myotis mystacinus 2 – 1 4 2 9 Myotis nattereri 1 2 2 5 9 14 5 38 Barbastella barbastellus – 1 3 2 3 2 – 11 Plecotus auritus 4 1 5 9 5 25 4 53 Total: 1709 2437 5762 2698 15106 8478 4706 40896 et al. 2019). bat migration in Pape in the autumn of 1985. Retie augi un Acknowledgements dzīvnieki 1986: 52–58. /in Latvian/ Gatke H. 1895. The Birds of Heligoland. Edinburgh, Scotland. We thank late Dr. Jānis Baumanis (1940 – 2006) for being the Lindecke O., Elksne A., Holland R.A., Pētersons G., Voigt C.C. soul and leader of the Pape station for 40 years (1966 – 2006). The 2019. Orientation and flight behaviour identify the Soprano trap construction in 2014 was financed by the Leibniz Institute pipistrelle as a migratory bat species at the Baltic Sea coast. J. for Zoo and Wildlife Research (Leibniz-Instituts für Zoo- und Zool. 308: 56–65. Wildtierforschung, Berlin, Germany), principal investigator Mihelsons H., Kasparsons Ģ. Lejiņš G., Vīksne J., Šmits V., Lipsbergs Dr. Christian C. Voigt, and implemented by us – Institute of J., Stolbovs I. 1960. Bird migrations in the Latvian SSR in the Biology, University of Latvia. We thank all involved personal and autumn of 1958. Latvijas Putnu dzīve – Ornitoloģiskie pētījumi numerous volunteers during all the years as well as our families 2. Latvijas PSR Zinātņu akadēmijas Bioloģijas institūta raksti for support during our fieldwork. We acknowledge Ivo Dinsbergs, XIV: 139–192. /in Latvian/ Ivars Kalvāns and Reinis Priedols for the drawings (Figures 1 and Payevsky V.A. 2000. Rybachy-type trap. In: Busse P. (ed.) Bird 2) and Jasja Dekker for the aerial image of the trap. Station Manual. Gdańsk University Press, Gdańsk, pp. 20–24. Pētersons G. 2004. Seasonal migrations of North-Eastern References populations of Nathusius bat Pipistrellus nathusii (Chiroptera). Myotis 41–42: 29–56. Baumanis J. 1995. Monitoring of migratory land birds in Pape Pētersons G., Celmiņš A. 1989. The greater mouse-eared batMyotis seashore. Report of the Institute of Biology of the Latvian myotis Borkhausen – a new species in the Latvian fauna. Retie Academy of Sciences to the Environmental Consultation augi un dzīvnieki 1989: 24–27. /in Latvian/ and Monitoring Center of the Ministry of Environment and Tuttle M.D. 1974. An improved trap for bats. J. Mammal. 55: 475– Regional Development of the Republic of Latvia. 24 p. /in 477. Latvian/ Weigold H. 1922. Die wissenschaftliche Vogelfangstation zu Belopolskii L.O. 1961. Activity of Biological Station of the Institute Helgoland. Naturwissenschaften 44: 960–964. of Zoology Acdemy of Sciences USSR 1956–1959. In: Ecology Weigold H. 1924. VII. Bericht der Vogelwarte der Staatl. and Migration of Baltic Birds. Riga, pp. 47–51. /in Russian/ Biologischen Anstalt auf Helgoland. J. Ornithol. 72: 17–68. Blūms P., Baumanis J., Baltvilks J. 1967. Catching of migratory Weigold H. 1956. How we began ringing on Heligoland. The Ring birds with nets 1966 in autumn in Latvia. Zooloģijas muzeja 8: 159–162. biļetens 1: 103–106. /in Latvian/ Woodford J., Hussel D.J.T. 1961. Construction and use of Celmiņš A., Baumanis J., Reinbergs A., Roze V. 1986. Intensive Heligoland traps. J. Field Ornithol. 32: 125–141.
Received 23 February 2021; received in revised form 4 March 2021; accepted 10 March 2021
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